Real-Time Ellipsometry at High and Low Temperatures

Among the many available real-time characterization methods, ellipsometry stands out with the combination of high sensitivity and high speed as well as nondestructive, spectroscopic, and complex modeling capabilities. The thicknesses of thin films such as the complex dielectric function can be determined simultaneously with precisions down to sub-nanometer and 10–4, respectively. Consequently, the first applications of high- and low-temperature real-time ellipsometry have been related to the monitoring of layer growth and the determination of optical properties of metals, semiconductors, and superconductors, dating back to the late 1960s. Ellipsometry has been ever since a steady alternative of nonpolarimetric spectroscopies in applications where quantitative information (e.g., thickness, crystallinity, porosity, band gap, absorption) is to be determined in complex layered structures. In this article the main applications and fields of research are reviewed.


■ INTRODUCTION
Ellipsometry measurements have already been made since the final decades of the 19th century pioneered by P. Drude. 1,2 The measurement performed by B. Pogany in 1916 can already be considered as a multi-wavelength measurement. 3 The term "ellipsometer" was coined in the article by A. Rothen in 1944 studying biomaterials on metal surfaces 4 revealing subnanometer sensitivity. The reason for the early appearance of this technique is that, by using ellipsometry, high sensitivity can be achieved without a coherent light source and any other very expensive and sophisticated components. The most important hardware component has been the computer, which serves both as a control for the measuring device and as a tool for analyzing the data, since most ellipsometers are polarization modulation devices computing the measured values by analyzing the temporal line shapes of intensity signals. The need for computation is the result of the increase in the number of publications in the field of ellipsometry, which started to accelerate in the 1980s (Figure 1), coinciding with the era of affordable computation becoming available worldwide.
Today, the range of applications of ellipsometry has diversified to basic research in physical sciences, semiconductors, and data storage solutions as well as biosensor, communication, flat panel displays, and optical coating industries. Since the 1960s, ellipsometry has been implemented to provide the sensitivity necessary to measure nanometerscale layers used in microelectronics resulting in increased interest at a steady rate in the field. In the 1980s, a rapid increase can be observed in both the development and the applications of ellipsometry (Figure 1). The real-time capabilities of ellipsometry were already utilized in the early 1980s. 5   Thomas 155 1997 Optical properties Vanadium oxides RT-300 M. Zorn 141 1997 Optical properties InP RT-875 C. Basa 55 1998 Monitoring of growth Si 873−933 R. Henn 26 1998 Synchrotron far-infrared Superconductor 10−300 B. Johs 67 1998 Growth control Hg 1−x Cd x Te 293−523 J. Koh 62 1998 Monitoring of growth Si 473 J. Lee 10 1998 Instrumentation Si 1085 W. Lehnert 18 1998 Integration in vertical furnace SiO 2 1200 J. Sǐk 137 1998 Optical properties Si 300−1200 M. Wakagi 50 1998 Phase transition Si 853−898 V.A. Yakovlev 70  Monitoring of growth Amorphous C 320 J.W. Klaus 115 2000 Monitoring of growth WN 600−800 P. Petrik 58 2000 Integration in vertical furnace Polysilicon 900 L. Pichon 131 2000 Transport properties Zr 973−1073 J.A. Zapien 28 2000 Instrumentation Thin films 523 P. Petrik 29 2001 Vertical furnace Polysilicon 873 P. Petrik 59  In this work, the presented studies of high-temperature (HT) or low-temperature (LT) ellipsometry are organized in three major groups: (i) instrumentation, (ii) monitoring of HT or LT processes, and (iii) determination of the reference dielectric functions at elevated or low temperatures (T). We exclude those investigations that focus on the ex situ characterization of the effect of HT (annealing) on the materials or structures and only deal with articles that measure real time at HT or LT. The number of ex situ characterizations is high, because both annealing and optical characterizations are basic methods in material processing and characterization. Numerous material properties that can be modified by annealing (e.g., band gap, crystallinity, porosity) can sensitively be measured and followed by optical methods.
We are only concerned here with real-time ellipsometry applications at temperatures higher or lower than room temperature (RT). Consequently, real-time optical measurements other than ellipsometry and real-time ellipsometry measurements at RT are excluded. Even so, looking at Figure  1, it is obvious that it is nearly impossible to include all the publications in the field in such a short review. Therefore, we only discuss a few significant achievements categorized by their type of applications and materials. In Table 1 we specify the topic and materials of all the papers discussed in this review ordered by the year of the work. We also include studies on processes at HT even if the temperatures have not been changed or the temperature dependence has not been investigated in real time (e.g., monitoring of growth at a given temperature).
Finally, in the majority of the articles the phrases "in situ" and "real time" are used more or less as synonyms. "In situ" is used if the integration of the measurement into a process is emphasized, whereas "real time" is used if the simultaneous measurement during the process is in focus. We use "real time" for both cases because it also implies that the characterization technique is integrated into the processing device.

■ INSTRUMENTATION
The majority of the real-time measurements presented in this review are based on homemade equipment, because commercial heat cells have not been available during most of the covered period of time. Many of the investigations utilize single-wavelength ellipsometry, which is sufficient in many cases to understand complex phenomena such as the oxidation of Si 6 or the evolution of surface roughness. 7,8 However, the development of spectroscopic ellipsometry (SE) 9 and the rotating compensator version 10 (later also double rotating compensator ellipsometry for the full Muller matrix analysis 11−13 ) have substantially accelerated the development of the field. Rotating compensator ellipsometry is not only more Only the name of the first author is given, with the corresponding reference and year in the first column.
suitable for real-time investigations but, due to the multichannel approach (measurement at each wavelength simultaneously at the same sensitivity�supported by the rotating compensator approach), the measurement time can also be decreased to the millisecond range while maintaining the spectroscopic capabilities. 14 A few of the developed instruments give access to ultrahigh temperatures. For example, J.C. Miller 15 measured the optical properties of seven metals up to T = 1873 K. T.T. Charalampopoulos et al. 16  Measurements conducted at ultralow temperatures also require special hardware and attention to the details. For the low-temperature measurements reported by Bjorneklett et al. 24 the samples were held in a vacuum cell with a cryostat. During the low-temperature experiments the sample chamber was filled with oxygen at a pressure of 15−25 kPa in order to avoid the condensation of oxygen onto the surface of the sample. Furthermore, an oxygen background atmosphere was chosen to avoid oxygen depletion of the Y−Ba−Cu−O sample surface during measurement at 80 K. To avoid small freeze-outs on the sample surface, Backstrom et al. 25 employed a measurement protocol with thermal cyclings between 10 K and room temperature between each pair of measured temperature points. R. Henn et al. 26 evacuated the total volume of the Fourier spectrometer, the prechamber, and the ellipsometer chamber simultaneously in order to eliminate spurious absorption by air molecules. The sample chamber was separated by an additional lid, which allowed them to reach a pressure of about 10 −6 mbar in the cryostat.
There have been special applications such as the combination of ellipsometry with other methods: M. Brown et al. 27 built an ultrastable oven for the HT investigation of liquid surfaces using X-ray reflectometry and ellipsometry. Other examples include the high photon energy SE by J.A. Zapien et al. 28 and the demonstration of SE in an industrial environment, integrating it into a vertical furnace by W. Lehnert et al. 18 to follow layer growth during batch processing ( Figure 2). 29 Integration of SE in a chemical vapor deposition tool has been demonstrated by C. Eitzinger et al. 30  Humlicek et al. 33 investigated superconducting materials at T = 20 → 300 K. R. Henn et al. 26 used synchrotron radiation farinfrared ellipsometry to determine the out-of-plane response of the HT superconductor La 2−x Sr x CuO 4 . The properties of the YBa 2 Cu 3 O 6.9 HT superconductor (superconducting transition T = 92.7 K) were investigated by wide-band (0.01−5.6 eV) SE. 34 The SE data provided real-time information on the optical self-energy in the normal and superconducting states. The optical conductivity σ, defined as ϵ(ω) = ϵ 1 (ω) + iϵ 2 (ω) = 1 + 4πiσ(ω)/ω (where ϵ and ω denote the dielectric function and the angular frequency, respectively), reveals a distinct feature at the superconduction transition temperature. 34 Optical properties of cuprite superconductors have been measured by A.V. Boris et al. 35 38 Understanding the growth of oxide on Si has been one of the major issues of microelectronics from the dawn of the technology. The kinetics of oxide growth has been studied by E. Irene et al. 39,40 already in the late 1970s using real-time SE, followed by several other studies of the same group, 41−43 also for silicides. 44 The real-time measurement of the oxidation of Si has also been demonstrated in a vertical furnace that has a smaller-sized system along with better contamination con- trol. 18,29 Laser-induced oxidation has been investigated by A.V. Osipov et al. 45 for T = 308 → 473 K.
Real-time monitoring and control of thin-film growth for photovoltaic applications is one of the key topics of HT SE, in which the temperature of the substrate is a critical process parameter. The majority of the studies deal with amorphous or microcrystalline Si and Ge, such as the growth of glowdischarge deposited amorphous Si (a-Si) and Ge (a-Ge) comparing the growth at RT and T = 523 K, developing models for the formation of nanoroughness, 46 or the formation of amorphous Si on transparent conductive oxides at T = 453 K. 47 The growth of amorphous Si was followed by real-time SE at T = 573 K, 48,49 and the crystallization of amorphous Si was observed at T = 853 → 898 K. 50 SE was proven to be a unique tool to reveal and optimize nucleation and a roughness layer separate from the bulk layer during thin-film growth (Figure 3 Rapid thermal chemical vapor deposition was used by C. Basa et al. 55 to create polycrystalline Si layers at T = 1123 K 56 and T = 873 → 933 K. Hot wire deposition has also been studied by Gupta et al. 57 at T = 323 → 788 K. W. Lehnert et al. 18 and P. Petrik et al. 58 demonstrated the integration of realtime SE in a vertical furnace by the example of thermal oxidation of Si and crystallization of a-Si, respectively. 29,59 The crystallization of Ge 60 Te 40 has also been investigated for T = 293 → 623 K. 60 The growth of amorphous Si films has been monitored by H. Fujiwara et al. 61 63 also developed real-time SE for the optimization of Si-based photovoltaic structures during hot wire chemical vapor deposition at T = 363 → 713 K. Silicon-based compound semiconductor structures have also been studied, such as the growth of graded Si 1−x Ge x films followed using real-time ellipsometry by N. Podraza et al. 64 at T = 473 → 533 K for the substrate. The same group, focusing on the investigations of photovoltaic materials, published in the same year a study on the deposition and growth of CdTe, CdS, and CdTe 1−x S x by J. Li et al. 65 using real-time SE at T = 418 → 593 K. A parametric B-Spline model 66 has been developed by B. Johs et al. 67 for Hg 1−x Cd x Te to control the composition during molecular beam epitaxial growth. The capability of SE to determine not only thicknesses but also both the real and imaginary parts of the dielectric function simultaneously has been utilized in many phase-transition studies in charge transfer solids (T = 150 → 400 K), 68 crystallization of amorphous Si 29,59 also in the presence of Al, 69 annealing of Si, 70 NiSi (T = 623 → 1023 K), 71  Formation and features of surface structures have been studied on GaAs (T = 474 K) 7 and strontium titanate surfaces (T = 293 → 1000 K). 79 S. Andrieu et al. 80 followed Sb adsorption on Si(111) at T = 998 K revealing adsorption/ desorption kinetics. H. Yao and P.G. Snyder 81 have presented real-time SE data from both oxidized and unoxidized surfaces of GaAs(100) at elevated temperature in ultrahigh vacuum. Real-time data showed the desorption of native oxide at approximately T = 850 K causing a surface roughening and degradation. Cleaning of the surface of Si wafers has been studied by Hu et al. 82 showing that the residual damage can be monitored by SE. This group also studied the etching of Si surface by Ar and H ions revealing a saturation of the damage layer with the etching time in case of Ar. 83 Thin film growth has been controlled for epitaxy of GaAs, 84 Al x Ga 1−x As 8,85 (also with control for parabolic composition profile 86 ), CdHgTe and CdTe/HgTe superlattices, 87 InAs, 88 and for metal organic CVD of AlGaAs and InGaAs (T = 873 → 973 K). 89 The capabilities of SE for a precise composition control during deposition has been demonstrated by D.E. Aspnes et al. 86 (Figure 4). B. Gallas et al. 90 investigated the formation of oxide layer on Si for reflective dielectric mirror applications, whereas S.C. Deshmukh et al. 91 monitored metal−organic vapor-phase epitaxy of GaN for optoelectronics. A versatility of other effects has also been investigated including oxidation of InSb/GaAs (T = 523 → 573 K) 92 and Si (T = 1200 K) 18 surfaces or HT effects in Li-doped ZnO. 93 Perovskites, langasite, and other special crystal structures have been studied for a broad range of applications. M. Kouaba et al. 94 explored the thermal properties of the perovskite slab alkylammonium lead iodide using real-time ellipsometry and numerous complementary methods. The thermal behavior of the excitonic absorption obtained by SE and PL showed a good quantitative agreement, but it was not possible to measure both the heating and cooling modes by SE due to the long data acquisition time (∼180 s) causing photodegradation of the material at HT. The ferroelectric ordering has been studied in SrTiO 3 and BaTiO 3 by Rossle et al. 95 at T = 4 → 700 K, with a special emphasis on its influence on the direct band gap close to the ferroelectric transition. It has been shown that the anomalous T-dependent shift of the direct band gap of SrTiO 3 is strongly affected by the Froḧlich electron−phonon interaction with the so-called soft mode that is at the heart of its quantum-paraelectric properties.
Piezoelectric materials of the langasite family have been investigated by T. Karaki et al. 96 Nucleation of diamond has been monitored during filament-assisted CVD at substrate temperatures of T = 300 → 1073 K. 97 S. Troiler-McKinstry et al. 98 studied the annealing of sol−gel ferroelectric thin films to follow the crystallization process at T = 773 → 873 K.
Dielectrics and Organic Materials. A large portion of real-time temperature-dependent ellipsometry studies on dielectrics includes polymers and organic materials. Compatibilization of immiscible polymer blends have been investigated by S. Yukioka et al. 99 at T = 443 → 483 K. Orientational dynamics in dye-doped organic electro-optic materials has been investigated by Apitz et al. 100 together with the temperature dependence of the phenomenon. It has been shown that the switching properties of the chromophores in a guest−host polymer composite based on Disperse Red 1 and poly(methyl methacrylate) hardly depends on the temperature. Bonaventurova-Zrzaveckáet al. 101 determined the temperature-dependent optical properties of an organic-inorganic polymer material poly(methyl-phenylsilane). They identified the onset of thermal degradation at T = 373 K. Below this temperature the optical response was reversible with an average shift of the lowest excitonic band of −8.5 × 10 −4 eV/K. Lipid bilayer modification by polyelectrolyte adsorption was investigated by Z.V. Feng et al. 102 using real-time ellipsometry. In this study, the melting temperature is lowered from 297 to 294 K of a phospholipid bilayer made from 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) when added with a weak polyelectrolyte, poly(methacrylic acid) (PMA). A slight asymmetry is also observed upon PMA addition in the gel phase, further verified by other characterization procedures.
In a special tool and application O. Santos et al. 103 monitored protein adsorption onto steel surfaces at T = 313 → 367 K, in which both the surface properties and the bulk solution conditions affected the adsorption rate. G. Demirel et al. 104 used polymer layers on a Si wafer for DNA sensing. Here, a validation test was conducted at T = 298 and T = 318 K, below and above the lower critical solution temperature value, respectively, on the Si(001) platform that interacted with the complementary of the probe "immobilized" oligo or the noncomplementary model oligo. It was confirmed that the hybridization between the probe and the target within the medium can be modulated. G. F. Malgas et al. 105 studied the temperature dependence of the phase separation in polymer− fullerene films. The study determined the optimum temperature to obtain the desired phase separation for solar cell application in P3HT:PCBM film, a methanofullerene derivative. The measurements using SE were made at multiple angles of incidence that showed a reduction in the electronic peaks of PCBM, causing an improved extinction coefficient and refractive index during annealing at 413 K.
Glass transition and thickness change has been investigated in polymers by A. Clough et al. 106 for T = 300 → 400 K. Both the change of the optical properties and the thickness have been monitored by real-time ellipsometry determining the major features of the kinetics ( Figure 5). Ogieglo et al. 107 investigated the glass transition in swollen polymers (polystyrene). For SE studies, a temperature stabilization system that operates in the range of T = 283 → 333 K was equipped to the test cell. Thermal equilibrium was maintained within the system, as polymer chains and penetrant mobility are large above glass transition temperatures, whereas the solvent concentration in the swollen matrix reduces when the temperature is lowered. T.J. Murdoch et al. 108 investigated enhanced ion effects in thermoresponsive polymer brushes by real-time ellipsometry. The thermoresponse of homo-and copolymer PMEO2MA brushes (size 540 ± 30 Å) in aqueous solution were characterized via different techniques. Ellipsometry measurements showed that the main impact of the  addition of salt is a displacement of the overall temperature response along the temperature axis, where increase in thiocyanate concentration up to 250 mM shifted the response to higher temperatures, while increasing acetate concentration shifted the response to lower temperatures. B.A. Humphreys et al. 109 investigated the thermoresponse of polymer brushes by the combination of SE and quartz crystal microbalance (QCM) for T = 293 → 318 K. HT ellipsometry has been reviewed recently for polymers by B. Hajduk et al. 110 The formation of mesostructured nanocrystalline titania thin films has been monitored by both real-time SE and X-ray diffraction (XRD) revealing a perfect complementary character, with SE showing the thickness and the porosity and XRD determining the crystallinity. 111 Bass et al. 112 investigated the pyrolysis, crystallization, and sintering of titania films assessed by real-time thermal ellipsometry. It is used to determine the evolution of porosity and characterization of the influence of parameters such as heating schedule, initial film thickness, nature of the substrate, solution aging, presence of water during calcination, nature of the templating agent, and influence of additives in the calcination environment as a function of temperature. Romanenko et al. 113 used real-time ellipsometry to determine characteristics of zirconia films formed on the surface of Zr during oxidation at T = 300 → 700 K.
Metals, Conductive, and Related Materials. There have been a few studies by SE in the 1990s on the evolution of optical properties of metals in both solid and liquid forms. Al has been studied by Nguyen et al. 114 up to T = 573 K. Phase transformation in metals has been measured by Krishnan et al. 19 using HT real-time laser polarimetry 17 at temperatures up to T = 2500 K. Wetting properties of the Hg-sapphire interface have been characterized using real-time ellipsometry at pressures and temperatures up to 144 MPa and T = 1773 K, respectively. 20 It was found that the highly precise detection of the wetting layer was possible on comparison of the R p and R s reflections, along with confirmation of the prewetting transition via a 45°reflection measurement setup using a wedge-shaped sapphire rod. Metallic materials can also be used as diffusion barriers, e.g., against Cu. The atomic layer deposition (ALD) growth of WN, one kind of those materials, has been monitored by J.W. Klaus et al. 115 to reveal a linear growth rate at T = 600 → 800 K. Another promising application of refractory metal nitrides is nanophotonics and plasmonics, for which the high-temperature optical properties are essential data. These have been determined for TiN by J.A. Briggs et al. 116 for T = RT → 1531 K.
The temperature dependence of plasmonic materials is also a hot topic. Wu et al. 117 have shown for T = RT → 873 K that the plasmonic properties of Ga nanoparticles can be tuned. Thermal stability has been revealed for Ag by H. Reddy et al., 118 which is a key factor in many other fields including solar materials. 119 The melting temperatures and HT phase transitions in Ag have been measured by S.A. Little et al. 120 up to T = 773 K. M. Schmid et al. 22 measured the optical properties of Au and Ag at T = 1700 K parametrized by Lorentz oscillators. In the case of Au samples, the refractive index (n) increases with increasing temperature in the solid as well as in the liquid phase, and the absorption coefficient (k) depicts the influence of the cracking up of the debris layers at high temperatures above the melting point on the surface of the liquid metal sample, while upon heating the Au sample below the melting point, the surface of the sample changed from a smooth surface to a satin-like texture and back to smooth again. For a Ag sample, the experimental value of the n decreases with increasing temperature below the melting point.
The oxidation of metal surfaces has been measured by numerous techniques that involve ellipsometry. The group of E.J. Mittemeijer measured in real time the initial stages of oxidation of a range of crystalline metal surfaces. A few studies used real-time ellipsometry alone, such as investigating the growth of ultrathin oxides on Zr 121 or MgAl alloys. 122 Another way is the combination of different methods either separately, such as the combination of depth profiling Auger electron spectroscopy and SE for the study of Zr oxidation, 123 passivation of Al surfaces, 124 and AlZr alloys, 125,126 or a simultaneous measurement such as the characterization of the surface by real-time SE and X-ray photoelectron spectroscopy (XPS) to investigate the initial stages of the oxidation of Zr, 123 Al, 124 and AlMg 127,128 (Figure 6). G. He et al. 129 oxidized Zr in thin-film form, where it was also studied by real-time SE at temperatures of T = 873 → 1173 K. The critical role of the sample surface in the HT optical properties of pure Fe and steel has been shown by A. Nebojsa et al. 130 for T = RT → 923 K. The authors identified the influence of the increased temperature on the magnetic contribution to the electronic interband transitions. Pichon et al. 131 revealed a complex mechanism during plasma nitridation of Zr at T = 973 → 1173 K. Oxidation on bare Zr substrates was performed at T = 375 → 773 K. At lower temperatures (423 K), oxidation stops after the first stage at a limiting thickness that increases with temperature (0.6 nm at 373 K; 0.7 nm at 423 K), while at T > 423 K a second stage of much slower, but continued, oxidefilm growth occurs. 123 The orientation-dependent oxidation kinetics has also been investigated on Zr by Bakradze et al. 132 Romanenko et al. 113   temperature in both crystalline and amorphous forms. The interband structure in crystalline Si shows three sharp peaks that are blended into a single broad peak in the amorphous samples. 133 147 References for metals have been determined in both liquid and solid forms. The optical properties of seven liquid metals have been measured by J.C. Miller 15 in an early pioneer work in 1969 up to T = 1873 K. Optical properties of Ag have been measured by S. Tripura Sundari et al. 148 in the photon energy range of 1.4−5.0 eV at T = 300 → 650 K, together with the thermo-optic coefficient using real-time SE. Temperaturedependent optical properties of Au have been determined to demonstrate experimentally that, upon optical excitation of the surface plasmon polaritons, a nonthermal electron population appears in the topmost part of the illuminated Au layer. 149 It has also been demonstrated that ellipsometry and polarimetry are capable of measuring the optical properties of materials in the liquid state. It has not only been discussed for the case of liquid metals shown above 150 but also for water. The temperature dependence of the optical properties of water has been determined by G. Abbate et al. 151 in 1978 revealing an exponential behavior, replacing a previously developed transmission-based method by ellipsometry. 150 As a special application, SE was used as a nonintrusive means of temperature measurement of Si wafer by Kroesen et al. 152 for T = 300 → 373 K. The detailed database on the temperature dependence of Si can also be used as a tool for the determination of the temperature. 136 This capability has been demonstrated by R.K. Sampson et al. 153 using Si in the temperature range from RT to 1173 K. The benefit of using shorter wavelengths than the usual 632.8 nm was pointed out, increasing the resolution of the temperature determination.
Reference optical data have been determined and analyzed for many oxide materials. K. Kamaras et al. 154 investigated the LT optical functions of SrTiO at T = 20 → 300 K. The optical properties of vanadium oxide have been measured by M.S. Thomas et al. 155 including the phase-transition temperatures. Li et al. 156 determined the optical properties of PtO x at T = RT → 973 K. PtO x is oxidized on heat treatment and then decomposes into Pt at 822 K. Condensation of porous Pt film occurs at T = 973 K for the samples with x > 1.3, where the surface roughness increases at T > 822 K. PtO x changes to metallic Pt via oxidization, decomposition, and condensation at elevated temperatures. B. Berini et al. 157 measured the reference dielectric function for the conductive oxide LaNiO 3 at T → 923 K. A change in the optical constants as a result of change in temperature was observed for T = 513 → 673 K.

■ CONCLUSIONS
Ellipsometry has been a widely used tool in the real-time characterization and monitoring of HT and LT processes since the 1960s. In the last decades, besides the initial application of superconducting, microelectronic, and semiconducting materials, new fields emerged including plasmonic, organic, and polymer applications. Similar to liquid metals in the early applications, now solid−liquid interfaces have also been investigated with temperature control and study of temperature effects. In many cases, vacuum chambers are replaced by small heat and liquid cells that can be used with table-top ellipsometers. Due to the sensitivity of SE to the crystalline order, the electron structure, and thickness of ultrathin films, an increase in applications is to be expected for 2D, perovskite, plasmonic, bio, and a range of other new materials.
program cofinanced by the Participating States and from the European Union's Horizon 2020 research and innovation program. Project No. TKP2022-EGA04 has been implemented with the support provided by the Ministry of Innovation and Technology of Hungary from the National Research, Development and Innovation Fund, financed under the TKP2021 funding scheme. Support by the ELKHcloud is also gratefully acknowledged.